1. Field of the Invention
This invention relates to a scanning microscope. This invention particularly relates to a scanning microscope provided with an improved mechanism for scanning a sample with a light spot. This invention also relates to a novel scanning mechanism for use in a scanning microscope.
2. Description of the Prior Art
Optical type scanning microscopes have heretofore been used. With the scanning microscope, a light beam is converged to a small light spot on a sample, and the sample is two-dimensionally scanned with the light spot. The light beam, which has passed through the sample during the scanning, the light beam, which has been reflected from the sample during the scanning, or the fluorescence, which is produced by the sample during the scanning, is detected by a photodetector. An enlarged image of the sample is thereby obtained.
As one type of the scanning microscopes, a confocal scanning microscope has heretofore been proposed. With the confocal scanning microscope, a light beam is produced by a light source and is condensed to a light spot such that an image of the light spot is formed on a sample. Also, a point image of the light beam, which has been radiated out of the sample, is formed and detected by a photodetector. The confocal scanning microscope is advantageous in that no pinhole need be located o the surface of the sample.
Basically, the confocal scanning microscope comprises:
i) a light source which produces a light beam, PA1 ii) a sample supporting member on which a sample is supported, PA1 iii) a light projecting optical means with which an image of the light beam is formed as a small light spot on the sample, PA1 iv) a light receiving optical means with which the light beam radiated out of the sample (i.e. the light beam, which has passed through the sample, the light beam, which has been reflected from the sample, or the fluorescence produced by the sample) is condensed, and an image of the PA1 v) a photodetector which detects the point image, and PA1 vi) scanning mechanism for two-dimensionally scanning the sample with the light spot. PA1 i) a sample supporting member on which a sample is supported, PA1 ii) a light source which produces a light beam, PA1 iii) a light projecting optical means with which an image of said light beam is formed as a small light spot on said sample, PA1 iv) a light receiving optical means with which the light beam radiated out of said sample is condensed, and an image of the condensed light beam is formed as a point image, PA1 v) a photodetector which detects said point image, PA1 vi) a movable member which supports said light projecting optical means and said light receiving optical means together, PA1 vii) a main scanning means which reciprocally moves said movable member such that said light spot scans said sample in main scanning directions, and PA1 viii) a sub-scanning means which moves said sample supporting member with respect to said movable member in sub-scanning directions, which are approximately normal to said main scanning directions, and at a speed lower than the speed at which said light spot scans said sample in said main scanning directions, whereby said sample is scanned with said light spot in said sub-scanning directions. PA1 i) a sample supporting member on which a sample is supported, PA1 ii) a light source which produces a light beam, PA1 iii) a light projecting optical means with which an image of said light beam is formed as a small light spot on said sample, PA1 iv) a light receiving optical means with which the light beam radiated out of said sample is condensed, and an image of the condensed light beam is formed as a point image, PA1 v) a photodetector which detects said point image, PA1 vi) a scanning means which moves said light projecting optical means and said light receiving optical means in synchronization with each other with respect to said sample supporting member such that said light spot scans said sample in main scanning directions and sub-scanning directions, and PA1 vii) an optical fiber having a first edge surface, on which an image of the light beam coming from said light receiving optical means is formed, and a second edge surface from which the light beam, which has entered said optical fiber from said first edge surface, is radiated to said photodetector, PA1 i) a sample supporting member on which a sample is supported, PA1 ii) an optical means which irradiates a light beam to said sample, and PA1 iii) a scanning means which moves said optical means with respect to said sample supporting member such that said light beam scans said sample, PA1 i) a material supporting member on which a material to be scanned is supported, PA1 ii) a light source which produces a light beam, PA1 iii) a light projecting optical means with which an image of said light beam is formed as a small light spot on said material to be scanned, PA1 iv) a light receiving optical means with which the light beam radiated out of said material to be scanned is condensed, and an image of the condensed light beam is formed as a point image, PA1 v) a photodetector which detects said point image, PA1 vi) a movable member which supports said light projecting optical means and said light receiving optical means together, PA1 vii) a main scanning means which reciprocally moves said movable member such that said light spot scans said material, which is to be scanned, in main scanning directions, and PA1 viii) a sub-scanning means which moves said material supporting member with respect to said movable member in sub-scanning directions, which are approximately normal to said main scanning directions, whereby said material to be scanned is scanned with said light spot in said sub-scanning directions. PA1 i) a material supporting member on which a material to be scanned is supported, PA1 ii) an optical means which irradiates a light beam to said material to be scanned, and PA1 iii) a scanning means which moves said optical means with respect to said material supporting member such that said light beam scans said material to be scanned,
An example of the confocal scanning microscope is disclosed in Japanese Unexamined Patent Publication No. 62(1987)-217218.
The conventional confocal scanning microscope utilizes one of the following scanning mechanisms:
(1) a mechanism which two-dimensionally moves the sample supporting member, and
(2) a mechanism which two-dimensionally deflects the light beam by a light deflector.
However, the scanning mechanism described in (1) has the problem in that the sample flies out of its correct position when it is scanned quickly. With scanning microscopes, samples of living organisms are often observed. If the quick scanning cannot be carried out during the observation of a sample of a living organism, subtle movements of the sample cannot be found. Also, a need exists widely for the real-time recording of images of various other samples. If the quick scanning cannot be carried out, such a requirement cannot be satisfied.
With the scanning mechanism described in (2), quick scanning can be achieved. However, the scanning mechanism has the drawback in that a light deflector, such as a galvanometer mirror or an acousto-optic light deflector (AOD), which is expensive must be used. Also, with the scanning mechanism described in (2), a light beam is deflected by a light deflector. As a result, the angle of incidence of the deflected light beam upon an objective lens of the light projecting optical means changes momentarily, and aberration is caused to occur. Therefore, the scanning mechanism described in (2) also has the problem in that it is difficult for the objective lens to be designed such that aberration can be eliminated. Particularly, in cases where an AOD is utilized, astigmatism occurs in the light beam radiated out of the AOD. Therefore, in such cases, a special correction lens must be used, and the optical means cannot be kept simple.